Phonograph decoupling apparatus

ABSTRACT

A record playing apparatus has a plurality of small area contact mounting devices distributed around confronting surfaces of a lower and upper turntable platter, the lower turntable platter being motor driven. The small contact area mounting devices comprise elongated members comprising substantially &#34;point contact&#34; at at least one end thereof. The small contact area mounting devices can be used to mount the base to a sub-base and/or the tone arm arrangement to the base of the record player.

BACKGROUND OF THE INVENTION

This invention relates to phonograph apparatus and method, and moreparticularly to an apparatus and method for decoupling a phonographrecord in order to prevent pick-up of noise generated in the variousmechanisms associated with a phonograph record playing device.

The purpose of the present invention is to provide a method and meanswhereby a playing phonograph record may be much better isolated from itsenvironment and thereby unburden the entire playback system from havingto reproduce those environmental acoustic disturbances normally pickedup by the cartridge in conventional record players.

The acoustic disturbances that this invention greatly reduces are thosetransmitted:

(a) to the base structure (structure born and airborne feedback;

(b) to the turntable playing surface or platter (structure born andairborne feedback and also motor rumble and main bearing rumble); and

(c) to the tone arm (same as in b above).

The above objects are achieved while still maintaining a substantiallyrigid and substantially non-compliant relationship between the tone armand record playing surface (a turntable platter) and at the same timeproviding a means to support and/or damp the record (same turntableplatter). A record damping mat is usually interposed between the recordand platter and also serves to damp the platter as well as the record.

SUMMARY OF THE INVENTION

In accordance with the present invention, a record playing apparatuscomprises a first motor driven turntable platter and a second turntableplatter mounted above said motor driven platter, the second platterpreferably having a spindle in the central portion thereof forengagement through the center opening of a phonograph record, the secondplatter being mounted to the first motor driven platter by means of aplurality of small contact area mounting devices distributed around theconfronting surfaces of the first and second platters. Preferably, threeor more small area mounting devices are provided between the first motordriven platter and the second platter.

In a preferred arrangement, the small contact area mounting devicescomprise a plurality of protrusions or projections, such as pins, havingpointed ends extending downwardly from the second platter. The firstmotor driven platter preferably has a groove(s) or receptacles forreceiving the pointed ends of the protrusions or projections, wherebythe second platter is mounted above the first platter. Instead ofprotrusions with pointed ends, elongated thin rods could be used.

In accordance with a further feature of the invention, the above type ofmounting technique is used for the tone arm mechanism and/or for thebase member on which the overall phonograph mechanism is mounted.

Various modifications may be made as discussed in the DetailedDescription hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of lower and upper turntables in adisassembled state;

FIG. 2 is a part sectional side view of the upper and lower turntablesmounted to each other;

FIG. 2A is an exploded view of the mounting pin arrangement of FIG. 2;

FIG. 3 is an exploded detail showing an alternate mounting pinarrangement;

FIG. 3a shows the receptacle 20 in top view.

FIG. 4 is an exploded detail showing yet another alternate mountingarrangement;

FIG. 5 is a perspective view of a turntable base mounted to a sub-basemember in its disassembled state;

FIG. 6 is a side view of the arrangement of FIG. 5 in its assembledstate, shown in partial cross-section to show one mounting pin;

FIG. 7 is a perspective view of a tone arm mounting arrangement in itsdisassembled state;

FIG. 8 is a side view of the arrangement of FIG. 7 in its assembledstate;

FIG. 9 is a side view of a modified tone arm mounting arrangement

FIG. 10 is a fragmentary view of a modified arrangement of the presentinvention;

FIG. 11 illustrates a further modification of the present invention;

FIG. 12 illustrates yet another embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a lower turntable platter 1 which is motor driven.The motor drive for the turntable platter 1 is not shown, but maycomprise a direct drive, belt drive, etc., or any other conventional orknown drive arrangements. The lower turntable platter 1 has a generallyV-shaped groove 2 extending around a peripheral portion of the uppersurface thereof. An upper turntable platter 3 having a spindle 4extending upwardly from the central portion thereof is mounted over thelower platter 1 by means of three downwardly extending elongated pins 5.The pins 5 have pointed tips 6 which are adapted to be received in thegroove 2. Preferably, in order to provide a minimum contact area betweenthe pins 5 and groove 2, the side walls 7 of the pins 6 are more sharplysloped upwardly than the side walls 8 of the groove 2. This is moreclearly seen from FIG. 2a. The purpose of the more sharply upwardlysloped side walls 7 is to provide a substantial point contact of the pin5 in the bottom of the groove 2. It has been found that the smaller thecontact area, the better the decoupling.

The V-shaped groove 2 may be segments of an arc instead of circular asshown in FIG. 1. The groove 2 may also comprise straight segments inregistration with associated pins 5. The circular arrangement of FIG. 1has the advantage that the platter 3 may be rotated relative to platter1 to obtain optimal balancing.

Any number of pins 5, or the like, may be provided. However, it has beenfound to be preferable to have as few pins 5 as possible. Three pins 5have been found to provide satisfactory results.

In order to further provide execellent decoupling of the phonographrecord from acoustic feedback, airborne feedback, turntable motor rumbleand main bearing rumble, it is further preferable to provide a spindle 4on the upper platter 3, rather than on the lower platter 1. It has beenfound that if the spindle 4 extends from the lower platter 1, thedecoupling effect is reduced.

The above described embodiment involves the use of pins 5 extendingdownwardly into a groove 2 of the lower platter 1. However, thearrangement could be reversed by providing pins 5 extending upwardlyfrom lower platter 1 and into a groove such as groove 2 formed in theconfronting surface of the upper platter 3.

While it is preferred to have as small a contact area as possiblecoupling the upper and lower platters together, it is preferred that thecontact areas cover less than 25% of the area of the lower roundturntable platter. As mentioned above, while it is preferred that thespindle 4 extend from the upper turntable platter rather than from thelower platter, the invention contemplates the possibility that thespindle could extend from the lower platter 1. In this case, the upperplatter 3 has a hole in the central portion thereof to permit thespindle extending from the lower platter to extend therethrough.

While the upper and lower platters are shown in FIGS. 1 and 2 as beingremovable relative to each other, it is possible to permanently orfixedly connect them at the point contact areas. The upper and lowerturntable platters are made of a substantially rigid material preferablyinherently having good damping characteristics, such as wood or somemetals.

The system of FIGS. 1 and 2 can also include some small compliances,such as hard rubber layers, as shown in the fragmentary view of FIG. 10.Referring to FIG. 10, an upper platter 3' of slightly differentconfiguration than the platter 3 of FIG. 1 has a hard rubber disc 10secured to the underside thereof, a metal or other rigid pin 5' beingsecured to the lower surface of the hard rubber disc 10. The pin 5',hard rubber disc 10 and platter 3' can be secured together at thevarious confronting surfaces by, for example, a suitable adhesive.Except for the provision of the hard rubber disc 10, the arrangement ofFIG. 10 is similar to that of FIGS. 1 and 2. The pin 5' engages agroove, such as V-shaped groove 2 in a lower platter 1. A plurality ofpins 5' are spaced around the platters, as in FIG. 1. Preferably threepins 5' are used. The hard rubber disc 10 preferably has a very lowcompliance. While the arrangement of FIG. 10 is suitable in many cases,the provision of the hard rubber disc 10 is not as preferred as thearrangement of FIGS. 1 and 2 wherein the hard rubber disc 10 is notprovided. While disc 10 is described as being made of hard rubber, othermaterials having similar characteristics may be used.

As shown in FIG. 11, a modified arrangement comprises a lower turntableplatter 11, preferably made of a substantially rigid metal and driven,for example by means of a motor connected to shaft 12. Platter 11 mayalternatively be belt-driven. A foam or other resilient layer 13 isprovided on the lower turntable 11 and a hard rubber layer 14 ispreferably provided on the foam layer 13. An upper substantially rigidmetal layer 15 is provided on hard rubber layer 14. The metal layer 15may have a smooth upper surface for receiving mounting pins 16 whichextend downwardly from the upper turntable platter 17 or may havegrooves such as grooves 2 of FIGS. 1 and 2. The upper turntable platter17 has a spindle 18 extending from the center thereof, the spindle 18not being coupled to the lower platter 11. The pins 16 are similar topins 5 of FIG. 1, or they may be mounted by means of a hard rubber layer10 having a very low compliance as shown in FIG. 10. It is preferred,however, in critical applications, not to use the hard rubber disc 10 ofFIG. 10.

The various layers of material on the lower turntable platter shown inFIG. 11 may be connected together by means of, for example, an adhesive,or the layers may be merely superposed one on the other and retained inplace by, for example, a central extension of shaft 12 extending throughthe center of the layers 11-15, but not contacting the upper turntableplatter 17. The metal layer 15 may have a V-shaped groove or grooves forreceiving the pointed ends of pins 16, similar to groove 2 of FIGS. 1and 2, or receptacles as shown in FIGS. 3 and 4 (discussed hereinbelow).

The pins 5, 5' illustrated in FIGS. 1, 2, 10 and 11 are preferably madeof a hard metal, carbon fiber material, or other similar materials. Thepins are preferably made of a rigid or substantially rigid material.

FIG. 3 illustrates a modified arrangement wherein instead of groove 2,the lower turntable platter 1 has receptacles 20 having a generallyconically-shaped upper opening 21 therein for receiving the pins 5 whichare attached to the upper turntable platter 3. The receptacles 20 areshown in top view in FIG. 3a. The operation and theory of thearrangement of FIG. 3 is substantially identical to that of FIGS. 1 and2. The receptacles 20 are mounted in blind bores in lower turntableplatter 1 and may be either press-fit in the bores, or may be connectedby means of an adhesive. While the mounting receptacles 20 are shown tohave a round outer periphery, they may be any desired shape, such assquare, rectangular, etc. The inclination of the walls of the conicalhole 21 is preferably greater than the inclination of the side walls ofthe pointed end 6 of the pin 5 so that the tip of the pin 5 presents asubstantially point contact in the bottom of the conical opening 21, theside walls of the pointed end 6 preferably not contacting the side wallsof the conical opening 21. The receptacles 20 may be surface mounted onlower platter 21, thereby eliminating the necessity of the blind boreshown in FIG. 3. Moreover, the pins 5 may extend upwardly from the lowerplatter 1 and engage receptacles 20, or the like, which are on theconfronting underside surface of the upper platter 3.

The arrangement of FIG. 3 may be modified as shown in FIG. 10, and/or asshown in FIG. 11 (receptacles 20 located on metal layer 15), as shouldbe apparent.

FIG. 4 illustrates a further modified arrangement wherein the upperturntable platter 3 has receptacles 30 attached thereto, and the lowerturntable platter 1 has receptacles 31 attached thereto. Extendingbetween the receptacles 30,31 are respective very thin rods 32 which aremounted in bores in respective receptacles 30,31. While FIG. 4illustrates only one such rod-type mounting arrangement, it should beclear that at least three are preferably provided distributed around theperiphery of the turntable platters 1,3. Compliances could be added tothe system of FIG. 4, similar to the arrangements of FIGS. 10 and 11.However, the compliances should be kept as low as possible, and as closein characteristics to a non-compliant system as possible. Anon-compliant system, of course, is preferred. The receptacles 30 may besecured to the undersurface of the upper turntable platter 3 by means ofan adhesive or other securing means, or may be embedded in bores inupper platter 3 similar to the manner in which receptacles 31 arereceived in bores in lower platter 1. The thin rods 32 are preferablymade of a substantially rigid metal material, carbon fiber material, orother suitable materials.

The preferably metal rods 32 and associated receptacles 30,31 may beformed in one piece, the rod 32 portion being turned down, for example,on a lathe. The larger ends 30,31 may be attached to the platters asdescribed above. Alternatively, the rods 32 may be inserted directlyinto bores in the platters and the enlarged receptacles may beeliminated.

FIG. 12 illustrates a further modified arrangement wherein the lowerturntable platter 1 is replaced by a spoke-like member 41 having a driveshaft 42 which may be, for example, motor driven. The spokes 43 may haveconical openings 44 drilled at the remote end portions thereof, groovesformed in the remote end portions (similar to groove 2 of FIG. 1), ormay have receptacles, such as receptacle 20 of FIG. 3, mounted at theend portions thereof for receiving associated pins 5 illustrated in theembodiments of FIGS. 1 and 2. Alternatively, the arrangement may befabricated with mounting pins 32 and associated receptacles 30,31 asdescribed above with respect to FIG. 4. Very low compliances can beadded, for example as shown in FIG. 10. Compliances, however, are notpreferred.

FIGS. 5 and 6 illustrate a further embodiment of the invention whereinthe base 50 of a turntable or record player is mounted to a lowermounting member 51 by means of pin-groove arrangements similar to thosediscussed hereinabove. Base 50, in the embodiment illustrated in FIG. 5,has four pins 52 extending downwardly from a lower surface member 53thereof. The lower surface member 53 is shown recessed in the base, butit may be flush with the bottom of the base 50, as desired. Pins 52 havepointed tip 54 and sloping walls 55 which form a conical end, similar tothe pins illustrated in FIGS. 1 and 2. Lower base member 51 has grooves56 formed therein for receiving the pointed ends of pins 52. The sidewalls 57 of the grooves 56 slope outwardly to a greater extent than dothe side walls 55 of pins 52 so that the pointed ends 54 of pins 52 makesubstantially point contact in the bottoms of the grooves 56. The pins52 are preferably of the same type of construction as mentionedhereinabove--that is, they are made of substantially rigid material,such as substantially rigid metal. More than four pins may be provided,and the pins may be provided in different arrangements than illustratedin FIGS. 5 and 6. Moreover, instead of grooves 56, receptacles such asshown in FIGS. 3 and 4 may be used. Still further, the grooves 56 neednot extend along the complete width of lower base member 51--they may besegments, if desired. The grooves 56 may extend lengthwise of the lowerbase member 51, either with or without the widthwise grooves 56 shown inFIG. 5. Small compliances can be added, for example as shown in FIGS. 10and 11, but the apparatus provides best effect if substantially nocompliances are included.

Instead of pins 52, elongated rod structures such as rods 32 andassociated receptacles 30,31 shown in FIG. 4 may be used. The elongatedrods, such as rods 32, may be removably installed in receptacles, orpermanently connected between the lower base member 51 and the upperbase member 50.

FIGS. 7-9 illustrate still further embodiments of the invention whereinthe inventive concept is used for mounting of a tone arm structure tothe turntable or record player arrangement. The tone arm structureillustrated in FIGS. 7-9 is generally mounted in the vicinity of acorner of a phonograph base member 50 so that the tone arm extends overthe record supporting platter. The mounting location of the tone armsupport structure of the present invention relative to the recordsupporting platter is conventional and is therefore not specificallyillustrated in the drawings. With respect to the mounting location ofthe tone arm support structure relative to the platter, reference ismade, for example, to U.S. Pat. Nos. 3,025,066 and 3,309,094.

As illustrated in FIG. 7, a tone arm 60 is mounted in a pivotingstructure 61, for example a gimbal-type structure or any otherconventional mounting structure, and is in turn mounted to a tone armbase member 62 which is mounted to the upper support surface 70 (FIG. 8)of a turntable base, such as base 50 of FIGS. 5 and 6. The tone armsupport arrangement is mounted to the tone arm support member 62 bymeans of, for example, a hollow bolt 63 through which lead wires from acartridge at the end of the tone arm 60 pass for connection to anamplifier, or the like. Typical lead wires are shown, for example, inFIG. 9 passing through the hollow bolt 63. The tone arm support member62 has three pins extending downwardly therefrom, said pins beinggenerally similar in construction to pins 5 illustrated in FIGS. 1 and2. The pins 64 are arranged to be received in receptacle members 65mounted on an intermediate ring member 66 which in turn is secured tothe upper support surface 70 of the base member 50, for example by meansof screws 71. The ring 66 is preferably made of substantially rigidmetal, as is the tone arm support member 62. As in the FIGS. 1 and 2embodiment, the pins 64 are preferably thin and made of substantiallyrigid material and the conical surfaces of the pins 64 are slopedupwardly to a greater degree than the conical surfaces of thereceptacles 65 so that the pins 64 make substantially point contact inthe bottom pointed receiving surface of the receptacles 65. The uppersupport member 70 of the base 50 has an opening 72 through which thehollow bolt 63 and lead wires may pass with clearance.

The tone arm support member 62 may merely rest on the receptacles 65, asshown in FIG. 8, or it may be bolted to the support member 70 of base 50from below, in a manner similar to that shown in FIG. 9.

The pins 64 may be provided in a different number than as illustrated inFIGS. 7-9. Also, the pins 64 may be replaced by, for example, supportmembers shown in FIG. 4, and if desired, very low compliances can beadded, as shown for example in FIG. 10. Preferably, compliances are notadded.

FIG. 9 shows a similar arrangement, but with an additional pin-supportedmounting plate located below the upper support surface 70 of the base.In the FIG. 9 arrangement, a ring 76, similar to ring 66 of FIG. 7, issecured to the support surface 70. Screws similar to screws 71 may beused, or a single nut and bolt may be used to commonly connect the upperand lower rings 66,76 to the base 70. In the embodiment shown in FIG. 9,the receptacles 65 are not used. Depressions or receiving conicalsurfaces are formed directly in the rings 66,76 for receiving the pins64,74 with substantially point-contact at the bottoms of the receivingconical openings. In this embodiment, washer-like members 77,78 arelocated over the opening in the center of the lower pin-holding member79 to cooperate with a nut 80 which threadably engages bolt 63. Similarwasher-like members 81,82 are provided, as required, for the purpose ofmounting the tone arm arrangement to the support member 62. It has beenfound that even by bolting the mounting device together as shown in FIG.9, excellent results are achieved. As in FIGS. 7 and 8, the pins 64 maybe replaced with mounting arrangements such as those shown in FIG. 4.Also, compliances such as in FIG. 10 can be added, but are notpreferable.

As mentioned above, any type of tone arm arrangement may be mounted tosupport member 62. Typical tone arms are shown, for example, in U.S.Pat. Nos. 3,025,066 and 3,309,094.

The platter mounting arrangement illustrated in FIGS. 1-4 and 10-12 canbe used alone, or can be used in combination with one or both of thebase mounting arrangement of FIGS. 5 and 6 and/or the tone arm mountingarrangement of FIGS. 7-9. Likewise, the base mounting structure of FIGS.5 and 6 can be used alone or in combination with any of the otherstructures, as can the tone arm mounting arrangement of FIGS. 7-9.

While the invention has been described above with respect to specificapparatus, it should be clear that various alterations and modificationscan be made within the scope of the invention as set forth in theappended claims.

I claim:
 1. A record playing apparatus comprising:a first motor driven,substantially rigid, turntable platter; a second substantially rigidturntable platter mounted above said motor driven platter with nofurther platters mounted therebetween, said first and second plattershaving confronting surface portions, said second platter adapted toreceive a record thereon; a plurality of low compliance small contactarea mounting devices, each of said mounting devices comprising asubstantially rigid, substantially inelastic protrusion or projection inthe form of an elongated pin fixed to and rigidly extending from one ofsaid first and second platters toward the other of said platters andeach having a free generally pointed end; receiving means on said otherof said platters for receiving and engaging said pointed free ends ofsaid small contact area mounting devices said receiving means comprisinga depression having a generally V-shaped cross-section such thatmovement of said other platter relative to said free ends of said smallcontact area mounting devices is prevented during operation of therecord playing apparatus; said small contact area mounting devices beingspaced from each other and being unconnected with each other, and beingdistributed around peripheral portions of said confronting surfaceportions of said first and second platters for providing a plurality ofisolated small contact, substantially rigid, support areas directlybetween said first and second platters and maintaining said confrontingsurfaces spaced from each other, the total of the cross sectional areasof said small contact area mounting devices being substantially lessthan the area of said platters in the plane of said platters, said firstand second platters being connected with each other only via said smallcontact area mounting devices; and a spindle in the central portion ofsaid second platter for engaging a center of a phonograph record, saidspindle not extending to said first platter.
 2. Record playing apparatusaccording to claim 1 wherein said pointed ends of said elongated pinsare generally V-shaped, and the angle of the V-shaped cross section ofsaid receiving means is greater than the angle of said V-shaped pointedends such that said free pointed ends of said elongated pins makesubstantially point-contact with a respective receiving means.
 3. Recordplaying apparatus according to claim 1 wherein said protrusions orprojections extend downwardly from said second platter and said firstplatter has said receiving means for receiving said protrusions orprojections.
 4. Record playing apparatus according to claim 1 whereinsaid receiving means comprises at least one groove for receiving andcontacting substantially only the pointed free ends of said protrusionsor projections.
 5. Record playing apparatus according to claim 1 whereinsaid receiving means comprises a plurality of receptacles distributedaround said other platter for receiving and contacting substantiallyonly the pointed free ends of said protrusions or projections.
 6. Recordplaying apparatus according to claim 1 wherein said small contact areamounting devices each comprises a thin elongated generally rod-shapedmember extending between said confronting surfaces of said first andsecond platters.
 7. Record playing apparatus according to claim 6wherein the free ends of said elongated generally rod-shaped members arefixedly and substantially rigidly received in respective receiving meansof said other of said platters.
 8. A record playing apparatuscomprising:a substantially rigid base; a motor driven turntable and atone arm mounted to said base; a substantially rigid sub-base membermounted below said base, with no further members co-extensive with saidsub-base interposed therebetween, said base and sub-base havingconfronting surface portions; a plurality of low compliance smallcontact area mounting devices, each of said mounting devices comprisinga substantially rigid, substantially inelastic protrusion or projectionin the form of an elongated pin fixed to and rigidly extending from oneof said base and sub-base toward the other of said base and sub-base,said protrusions each having a free generally pointed end; and receivingmeans on said other of said base and sub-base for receiving and engagingsaid pointed free ends of said small contact area mounting devices saidreceiving means comprising a depression having a generally V-shapedcross-section such that movement of said other of said base and sub-baserelative to said free ends of said small contact area mounting devicesis prevented during operation of the record playing apparatus; saidsmall contact area mounting devices being spaced from each other andbeing unconnected with each other, and being distributed aroundperipheral portions of said confronting surface portions of said baseand sub-base for providing a plurality of isolated small contact,substantially rigid, support areas directly between said base andsub-base and maintaining said confronting surfaces spaced from eachother, the total of the cross sectional areas of said small contact areamounting devices being substantially less than the area of saidconfronting surfaces in the plane of said confronting surfaces, saidbase and sub-base being connected with each other only via said smallcontact area mounting devices.
 9. Record playing apparatus according toclaim 8 wherein said pointed ends of said elongated pins are generallyV-shaped, and the angle of the V-shaped cross section of said receivingmeans is greater than the angle of said V-shaped pointed ends such thatsaid free pointed ends of said elongated pins make substantiallypoint-contact with a respective receiving means.
 10. Record playingapparatus according to claim 8 wherein said elongated pins extenddownwardly from said base and said sub-base has said receiving means.11. Record playing apparatus according to claim 8 wherein said receivingmeans comprises at least one groove for receiving and contactingsubstantially only the pointed free ends of said elongated pins. 12.Record playing apparatus according to claim 8 wherein said receivingmeans comprises a plurality of receptacles distributed around said otherof said confronting surfaces for receiving and contacting substantiallyonly the pointed free ends of said elongated pins.
 13. Record playingapparatus according to claim 8 wherein said small contact area mountingdevices each comprises a thin elongated generally rod-shaped memberextending between said confronting surfaces.
 14. Record playingapparatus according to claim 13, wherein said elongated generallyrod-shaped members are fixedly and substantially received in respectivereceiving means of said other of said base and sub-base.
 15. A recordplaying apparatus comprising:a substantially rigid base; a motor driventurntable platter on said base; a tone arm arrangement; and a tone armarrangement mounting structure, said mounting structure comprising:asubstantially rigid tone arm mounting plate-like member mounted to saidbase with no members substantially co-extensive with said plate-likemember mounted therebetween, said substantially rigid plate-like memberand said base having confronting surface portions; a plurality of lowcompliance small contact area mounting devices, each of said mountingdevices comprising a substantially rigid, substantially inelasticprotrusion or projection in the form of an elongated pin fixed to andrigidly extending from one of said base and plate-like member toward theother of said base and plate-like member, said protrusions each having afree generally pointed end; and receiving means on said other of saidbase and plate-like member for receiving and engaging said pointed freeends of said small contact area mounting devices said receiving meanscomprising a depression having a generally V-shaped cross-section suchthat movement of said other of said base and plate-like member relativeto said free ends of said small contact area mounting devices isprevented during operation of the record playing apparatus; said smallcontact area mounting devices being spaced from each other and beingunconnected with each other, and being distributed around peripheralportions of said confronting surface portions of said base andplate-like member for providing a plurality of isolated small contact,substantially rigid, support areas directly between said base andplate-like member and maintaining said confronting surfaces spaced fromeach other, the total of the cross sectional areas of said small contactarea mounting devices being substantially less than the area of saidconfronting surfaces in the plane of said confronting surfaces, saidbase and plate-like members being connected with each other only viasaid small contact area mounting devices.
 16. Record playing apparatusaccording to claim 15 wherein said plate-like member is mounted fromabove said base; and further comprising:a second plate-like memberhaving an upper surface portion which confronts a lower surface portionof said base; and a further plurality of said substantially rigid smallcontact area mounting devices in the form of elongated pins distributedaround peripheral portion of said confronting surface portions of saidsecond plate-like member and base and providing a plurality of saidsmall contact support areas directly between said second plate-likemember and base and maintaining said confronting surface portionsthereof spaced from each other.
 17. Record playing apparatus accordingto claim 15 wherein said receiving means receives and contactssubstantially only the pointed free end of said protrusion orprojections.
 18. Record playing apparatus according to claim 15 whereinsaid receiving means comprises at least one groove for receiving andcontacting substantially only the pointed free end of said protrusionsor projections.
 19. Record playing apparatus according to claim 15wherein said receiving means comprises a plurality of receptaclesdistributed around said other of said confronting surfaces for receivingand contacting substantially only the pointed free ends of saidprotrusions or projections.
 20. Record playing apparatus according toclaim 15 or 16 wherein said small contact area mounting devices eachcomprises a thin elongated generally rod-shaped member extending betweensaid associated confronting surfaces.